Contaminated surfaces are an important potential source for transmission of Clostridium difficile. However, interventions to improve environmental cleaning have not consistently been effective in reducing the incidence of C. difficile infection (CDI). Moreover, there is considerable uncertainty regarding optimal strategies to monitor the effectiveness of environmental disinfection. The goal of this application is to develop evidence-based strategies to improve environmental disinfection and to test their effectiveness in reducing rates of healthcare- associated CDI. Our central hypothesis is that an evidence-based intervention to improve environmental disinfection will reduce rates of healthcare-associated CDI. The specific aims of our proposal are: 1). Validate the effectiveness of the fluorescent marker method as a means to monitor disinfection of high-touch surfaces in CDI rooms. To accomplish this aim, we will correlate removal of fluorescent marker from high-touch surfaces in CDI rooms with removal of spores based on culture and PCR of toxin B genes. 2). Determine if daily disinfection of high- touch surfaces during CDI treatment will reduce healthcare worker hand contamination. To accomplish this aim, we will perform a prospective, randomized trial to compare standard cleaning (i.e., high-touch surfaces only cleaned if soiled) of CDI rooms versus standard cleaning plus daily decontamination of high-touch surfaces. The primary outcome measure will be healthcare worker hand contamination. and 3). Determine if an intervention to improve environmental disinfection by housekeeping staff will reduce rates of healthcare-associated CDI. To accomplish this aim, we will perform a 12-month randomized trial of 16 Cleveland area hospitals to compare standard housekeeping cleaning to enhanced cleaning with ongoing monitoring and feedback. The primary outcome measure will be incidence of healthcare- associated CDI. Our laboratory is ideally poised to accomplish the proposed research because we have extensive experience investigating the role of the environment in pathogen transmission and in evaluation of disinfection methods. The results will be significant because CDI is an important cause of morbidity and mortality and because there is a need for development of optimal environmental disinfection strategies to prevent transmission. The Department of Health and Human Services Action Plan to Prevent Healthcare-Associated Infections identified development and assessment of the impact of a Clostridium difficile environmental cleaning bundle as an important unmet need.